The Milky Way has about 300 billion stars. A star’s architecture is such that it shines because of the radiation from its interior. The radiation is caused by Nuclear Fusion in which a light element like hydrogen is converted to a heavier element like helium. This process is called nucleosynthesis and also occurs in our sun. Any star achieves nuclear fusion at its core by rising to a temperature of 4,000,000 degrees Kelvin or higher. Over time stars like the sun will run out of hydrogen and collapse into what is known as a dense white dwarf star. Other stars which are more dense than the sun can explode into a supernova and become a super dense neutron star or black hole.